The present invention relates to a device for communicating between two media separated by a slotted wall through which passes a gripping or remote manipulation arm.
The automatic manipulation and displacement of objects in ultra-clean enclosures, particularly in the semiconductor industry, makes it necessary to place outside of the enclosures the movement transmission mechanisms and motors, which raise a lot of dust as a result of their vibrations. Therefore they are placed behind a wall defining the ultra-clean enclosure. A slot is made in the wall for the passage of an arm.
In the case of an arm subject to translations perpendicular to its axis, the slot is elongated, which causes serious sealing problems. Although it is necessary to maintain a high pressure condition in the ultra-clean enclosure in order to produce an air current to the outside and thus constitute an obstacle to the impurities and dust, the communication surface must not be excessive because ventilation then becomes costly.
A frequently used solution consists of joining the contours of the slot and the arm by deformable membrane or diaphragm. However, this still leads to dust appearing as a result of displacements of said membrane, while causing mechanical limitations to the movements of the arm and, in the long term, wear due to membrane fatigue.
French patent 2 226 888 describes a membrane formed by two contiguous lips for covering a slot. The edges or borders of the lips are joined by mortise and tenon sections which can be fitted into one another, or by means of magnets having opposite polarity. A slider slides between the edges and locally separates them, while squeezing them in the slides. Thus, it is in fact a double Eclair closure, more commonly called a zipper. This device cannot be used in the technical field of the invention, because it involves significant mechanical contacts giving rise to dust.